4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Paul Burton <paul.bur...@imgtec.com> [ Upstream commit d4da0e97baea8768b3d66ccef3967bebd50dfc3b ] If a driver causes DMA cache maintenance with a zero length then we currently BUG and kill the kernel. As this is a scenario that we may well be able to recover from, WARN & return in the condition instead. Signed-off-by: Paul Burton <paul.bur...@mips.com> Acked-by: Florian Fainelli <f.faine...@gmail.com> Patchwork: https://patchwork.linux-mips.org/patch/14623/ Cc: Ralf Baechle <r...@linux-mips.org> Cc: linux-m...@linux-mips.org Signed-off-by: Sasha Levin <alexander.le...@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- arch/mips/mm/c-r4k.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -712,7 +712,8 @@ static void r4k_flush_icache_range(unsig static void r4k_dma_cache_wback_inv(unsigned long addr, unsigned long size) { /* Catch bad driver code */ - BUG_ON(size == 0); + if (WARN_ON(size == 0)) + return; preempt_disable(); if (cpu_has_inclusive_pcaches) { @@ -745,7 +746,8 @@ static void r4k_dma_cache_wback_inv(unsi static void r4k_dma_cache_inv(unsigned long addr, unsigned long size) { /* Catch bad driver code */ - BUG_ON(size == 0); + if (WARN_ON(size == 0)) + return; preempt_disable(); if (cpu_has_inclusive_pcaches) {
